This invention relates to communication and, more particularly, to effective bandwidth utilization in an environment where transmission is in the form of information frames.
One illustration of such an arrangement where data is processed and transmitted in frames is Orthogonal Frequency Division Multiplexing (OFDM), where different symbols of a frame are transmitted over different frequency sub-bands (frequency bins). The communication channel typically has a non-uniform frequency response, and this non-uniformity results in non-uniform error probability values for different sub-bands, (frequency bins) in a frame. Thus, the frame in an OFDM arrangement can be viewed to exist along the frequency axis, and the symbols are placed in the frequency bins along the frequency axis.
Another illustration is an arrangement where a receiver's clock is periodically synchronized to a transmitter's clock. The period between synchronization instances can be viewed as a frame, and in such arrangements, because of clock synchronization degradation as the frame progresses, information modules that are sent at the beginning of the frame, i.e., shortly after synchronization, have a lower error probability than information modules that are sent at the end of the frame. Thus, in such an arrangement the frame is along the time axis, and the bins occupy different time intervals along the time axis.
Yet another illustration relates is an OFDM arrangement that also employs a periodic resynchronization of the receiver's clock, and that imparts to the arrangement the notion of a frame that includes bins along both the time axis and the frequency axis.
In the context of this disclosure, a frame is a unit of information transmission in connection with which information-carrying bins that make up the frame have transmission error probabilities that characterize the respective bins.
These symbol error probability dynamics present a challenge and an opportunity to communication system design.